1. Field of the Invention
The present invention relates to a ceramic filter and more particularly relates to a ceramic filter that can be used for a long time at a high temperature.
2. Description of Related Art
A ceramic filter including a ceramic porous body is reliable because it has excellent mechanical strength and durability in comparison with those of a polymer film. A ceramic filter has a high corrosion resistance as well, and so it is not degraded during chemical washing with acid, alkali or the like. A ceramic filter further can be controlled precisely in its average pore size that is a factor to determine the filtration ability. Since a ceramic filter has such various advantages, such a filter has been used in the wide range of field including not only the field of water treatment and exhaust gas treatment but also the field of pharmaceutical and food so as to filter out suspended matter, bacteria, dust and the like existing in a fluid such as liquid and gas for removal. A ceramic filter has been used for other purposes also for pervaporation to separate and purify the mixture of liquid containing two or more ingredients and for gas separation to separate and purify the mixture of gas containing two or more ingredients.
Ceramic filters used, for example, include a columnar porous substrate, a separation membrane disposed on a wall face in a cell, and glass seal (an end-part glass sealing portion) disposed so as to cover an end face of the porous substrate. Herein the columnar porous substrate includes a plurality of “cells extending from its one end face to the other end face.” In addition, the columnar porous substrate is made of ceramic. Thereby, such a columnar porous substrate allows fluid permeability inside the element to be enhanced while keeping the filtration performance (see Patent Document 1, for example).